Unless you are an established organization. I don't see why anyone will move away from APIs or finetuning. Custom models are going to get fewer and far between.
That's another problem with that article. The gap between API and fine-tuning is much smaller than the gap between fine-tuning and developing a foundation model. I would look at BloombergGPT as an example
here you have a company which can make a document collection about the same size as "The Pile", add that to "The Pile" and train a model based on that. They're not just a big company but they are in the information business so it is clear that it's worth it to them.
https://arxiv.org/abs/2303.17564
here you have a company which can make a document collection about the same size as "The Pile", add that to "The Pile" and train a model based on that. They're not just a big company but they are in the information business so it is clear that it's worth it to them.